Panic door

ABSTRACT

A panic door assembly which provides a secure closing due to a special laterally displaceable edge element attached to the free side of the door. The edge element mates with either an adjacent door or a door frame when the door is closed and locked and the edge element is laterally displaced by the door handle to open the door. Where two doors are mounted to a door frame so that they meet at their free sides when closed, each of the doors may be provided with a laterally displaceable edge element, and the confronting profiles of the two edges are made to interengage one another when the doors are locked. With independently operated edges, either door can be opened individually. Either one or both of the doors may additionally include a bolt mechanism for securing the doors to the frame in a locked position.

United States Patent 'lavano PANIC DOOR [72} inventor: John B. Tavano, 20 Edgewood Drive, Torrington, Conn. 06790 [22] Filed: Mar. 4, 1970 [21] Appl. No.: 16,414

Primary Examiner-Kenneth Downey Attorney-Fishman and Van Kirk [5 7] ABSTRACT free side of the door. The edge element mates with either an adjacent door or a door frame when the door is closed and locked and the edge element is laterally displaced by the door handle to open the door. Where two doors are mounted to a door frame so that they meet at their free sides when closed, each of the doors may be provided with a laterally displaceable edge element, and the confronting profiles of the two edges are made to interengage one another when the doors are locked. With independently operated edges, either door can be opened individually. Either one or both of the doors may additionally include a bolt mechanism for securing the doors to the frame in a locked position.

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PANIC noon BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to the field of doors and more particularly to the field of panic doors which may be opened from one side simply by pressing an actuating handle.

2. Description of the Prior Art Doors which may be readily opened in the event of an emergency are known and numerous patents such as US. Pat. Nos. 2,886,960; 2,908,523 and 2,959,440 have been issued on such doors.

The environment in which such doors are used frequently is associated with a building visited by or housing a large number of people. Public buildings such as theatres, municipal buildings, office buildings, churches and schools, among others, require a means of ready exit in the event of a fire or other emergency which necessitates a rapid and unexpected evacuation by personnel. Since the number of doors required to rapidly evacuate a building is more than that normally required or desired for the routine traffic in and out of the building, it is frequently desired to limit the use of selected doors to emergency or other special circumstances. Access from the outside is denied by locking the doors through a handle actuatable only from the inner side of the building. Since the door may remain closed for extended periods of time and because it is most imperative that the door open immediately in the event of an emergency, the reliability of any mechanism which locks the panic doors must be extremely high. Furthermore, since the panic doors are frequently distributed throughout the building in areas which are seldom frequented by building personnel, such doors must be extremely secure against tampering from without by individuals attempting to gain unauthorized entrance to the building.

The requirements of such a door accordingly demand the utmost in reliability due to the inherent use for which the doors are intended and strength to withstand all types of forcible entry to which the public buildings are exposed. While these two requirements are distinct, it will be readily understood that there is an element of conflict between the two, one requiring that the doors open easily, and the other requiring that the doors stay closed.

Panic doors which are installed in duplicate sometimes emloy a center post to which both of the doors may be bolted for security. In the event that personnel must exit the building rapidly, impediments such as the center post greatly reduce the effectiveness of the emergency doors. Panic doors without a center post usually employ a bolt or latching mechanism at the top and bottom of the door to secure the door in the frame. Additionally, a latch which couples one of the doors to the other door may be provided. The outer surface of the door would include an overlapping cover plate to forestall forcible entry from outside the building by means of prybars or other unlatching tools. Without firm contact between either the doors themselves or the post, unauthorized access is more easily gained.

It is accordingly an object of the present invention to disclose a panic door assembly which may be readily opened from inside the building.

It is a further object of the present invention to disclose a panic door assembly which when closed and locked provides improved security against unlawful, forcible entries.

It is still a further object of the present invention to disclose a panic door assembly which, when opened, affords minimal resistance to the exit of personnel.

SUMMARY OF THE INVENTION This invention relates to the field of door assemblies and more particularly to emergency doors or panic doors which may be readily opened from inside a building and which may not be easily forced opened from without the building.

In its simplest embodiment, the invention is concerned with a single door which is hinged to a door frame at one side. The

opposite, free side supports a laterally displaceable edge element which mates with either an adjacent door or a door frame when the door is in its closed position. The door may also have a bolt at the top of the door and a latch at the bottom of the door to lock the door to the door frame. An operating handle is mechanically connected to the edge element to disengage it from its mating part and may simultaneously disengage the top bolt and bottom latch whereby the door can be opened.

The displaceable edge element extends substantially the full length of the free edge of the door and is forced against the abutting structure when the door is locked by means of springs and a three-bar mechanical linkage. The linkage is placed in a toggle position when the door is locked and, accordingly, greatly increases the force butting the edge element against the adjacent structure.

A spring connected to the mechanical actuating linkage normally urges the actuating linkage toward the locked position. A spring-loaded catch automatically secures the linkage in the unlocked position when unlocked by the operating handle. The catch has a release which engages the door frame as the door moves into the closed position. The release displaces the catch to permit the mechanical linkage to move to the locked position.

In another, and the more usual, embodiment of the invention, two doors are pivoted from opposite sides of a door frame and the doors have mating edge elements at their free side edges. The edge element of one or, preferable, both doors is laterally displaceable by means of a mechanical operating linkage and an operating handle. One of the doors includes a locking bolt so that the two doors together may be secured to the door frame. The bolt engages a self-centering cup. The cup is resiliently mounted in the crossbeam of the door frame so that initial misalignment of the bolt and the cup does not distort or destroy the bolt receiving aperture of the cup. The door having the bolt may also include a latch at the bottom side which engages a mating lip in the doorsill. If desired, bolts and latches may be incorporated on each of the doors. To insure that prying tools may not be inserted between the doors inspite of the interacting forces of the jams, each of the mating surfaces of the edge elements may have tongue-and-groove profiles.

BRIEF DESCRIPTION OF THE DRAWINGS The novel door assembly is depicted in several views of the drawings and like parts are designated with like numerals throughout the various figures.

FIG. I discloses'the panic doors installed in and opening outwardly from a wall of a building.

FIG. 2 is a view of the free end of one of the doors partially broken away to show the mechanical actuating linkage as viewed along the line 2-2 in FIG. 1.

FIG. 3 is an enlarged sectional view of the top and bottom of the door seen in FIG. 2 with the actuating mechanism and edge element in the unlocked position.

FIG. 4 is a sectioned view of the bottom of the door seen in FIG. 3 after the actuating mechanism and edge element have been moved to the locking position.

FIG. 5 is an isometric view of the three-bar linkage which actuates the edge element.

FIG. 6 is a top view of the door locking mechanism as viewed along the line 6--6 in FIG. 3 after the edge element has been displaced to its closed position.

FIG. 7 is a sectional view of the self-centering, bolt-receiving cup on the door frame.

FIG. 8 is a transverse sectional view of the doorsill and the bottom of the door in the locked position.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference to FIG. 1 discloses the improved panic door assembly in one embodiment as it would be installed at the exit of a building. The assembly 10 is composed principally of a door frame 12, a left-hand door 14 and a right-hand door 16. The frame is basically a rectangular frame and consists of two lateral hinge posts 18 and 20, a crossbeam 22 connecting the hinge posts at their upper ends and a doorsill 24 connecting the hinge posts at their bottom ends. The left-hand door 14 is hung to the hinge post 18 by means of three hinges 26. The right-hand door 16 is similarly hung to hinge post by three hinges (not visible). While three hinges are employed, it is contemplated within the scope of the present invention that a single piano hinge extending the entire length of the door or several piano hinges extending along portions of the doors or other types of hinges may be employed without departing from the essential purpose of pivotally mounting the doors to the frame 12.

Referring now to the doors l4 and 16 themselves, which are counterparts having the same basic construction, the principal structural members of the door consist of channel members 28, 30 32 and 34. The channel members form the structural framework for the door which is filled by a large, central, heavy plate, glass pane 36. The channel members 28-34 have a hollow box construction and may be formed from a suitable material such as stainless steel or an anodized metal. The particular material will depend, of course, on the appearance desired and the atmosphere to which the door is exposed. The glasspane 36 is made from a sturdy doorglass and provides additional structural rigidity to the channel members in their assembled form. While the doors shown employ the central glasspane, it may be preferable in certain instances to fill the central portion of the door with an opaque material such as the metal which forms the channel members or a laminated lightweight material such as wood covered with sheet metal for fire resistance. The construction of the body of the door is, therefore, a conventional construction and any number of available materials or decorative arrangements can be incorporated in the construction without departing from the spirit of the present invention.

The doors l4 and 16 are viewed in FIG. I from outside of a building and consequently the doors are shown opening outwardly as frequently required by fire regulations. To open a door, a pivotal operating handle 38 mounted to supports 40 is pressed downwardly. The operating handle 38 on at least one of the doors operates latching and bolting mechanisms to release the doors from their closed and locked positions with the frame 12. Since it is desirable to prevent unauthorized access to the building, no handles are provided on the external surfaces of the doors for either releasing the locked doors or pulling the doors open. Of course, if exterior handles are desired, they may be incorporated in a conventional manner.

FIGS 1-4, 7 and 8 show the mechanism which permits the door 14 to be locked to frame 12 and unlocked through the operation of handle 38. The free channel member 32 opposite the hinged channel member 28 contains a cartridge 33 which houses the locking and the bolting mechanisms. The cartridge 33 can be welded into channel 32 or connected to channel 32 by other suitable means. The upper end of cartridge 33 includes a bolt 42 which is displaceable upwardly with an operating rod 44 carried in guides 45. The bolt 42 engages a self-centering bolt receiver 46 in the crossbeam 22. The receiver 46 as seen in FIG. 7 is composed basically of the cup 48, a cylinder 50 and a biasing spring 52. The cup which has a cylindrical body slides vertically in the cylinder 50 and is biased downwardly by means of the spring 52. In order to retain the cup in the cylinder 50, a snap ring 54 is mounted in the groove 56 near the base of the cylinder 50. The spring 52 permits the cup 48 to displace vertically in the event that perfect alignment between the bolt 42 and cup 48 does not exist when the bolt is displaced upwardly on operating rod 44. If the bolt 42 were engaged by a fixed aperture in crossbeam 22, slight misalignments as the bolt engaged the aperture would cause substantial abrasion or wear and could eventually destroy a tight fit between the doors and the frame. The vertical displacement of cup 48 permits the bolt to be initially engaged while it is slightly off center and the spring 52 then urges cup 48 downwardly over the misaligned bolt 42 while the mating conical surfaces on both the bolt and cup center the bolt and bring the door to its closed position. The self-centering operation of the receiver 46, therefore, provides a more reliable and durable locking mechanism and reduces wear of the bolt receiving hole in the frame.

While the upper end of the door is secured by moving a bolt into a receiving aperture, such apertures in the bottom doorsill are not preferred due to the opportunities for dirt to clog the aperture and interfere with any locking action of the bolt. As seen in FIGS. 3, 4 and 8, the lower end of the cartridge 33 includes a latch 58 which is pivotally mounted in a strut 60 by means of fastening pin 62. The latch 58 is connected at one end through a linkage mechanism to operating rod 44 which is guided by strut 60. At the other end, latch 58 has a tang 64 which is rotatable to engage the inside surface of a lip 66 (see FIG. 8) on the doorsill 24. As the latch 58 is pivoted by means of the operating rod 44, the tang 64 rotates into contact with the lip 66 as shown in FIG. 8. The tang 64 may have a chamfered surface confronting the lip 66 to eliminate slop at the interface of the tang 64 and lip 66.

FIG. 8 shows a weather strip 70 secured to the lower edge of the door. The strip 70 contacts the outer surface of the lip 66 and thereby provides a weather seal at the lower edge of the door. The strip 70 extends substantially the entire width of the door and may be held to the base of the door by means of clamping screws 72 which screw into the strip 70 through oblong holes in the hinged edge and free edge of the door whereby the strip can be adjusted vertically.

It will be understood that by means of the latch 58 and the bolt 42, the door may be secured to the frame 12 at both the top and the bottom of the free edge. An attempt to enter the building by prying open the top or bottom of the door will be substantially thwarted when the door is thus secured and its displaceable edge is mated (as more fully described hereinafter).

To actuate the bolt 42 and latch 58 by means of operating rod 44, the handle 38 is connected through the channel member 32 and cartridge 33 to an actuating fork which engages a collar 82 fixed to the rod 44 so that downward motion of the handle 38 causes a corresponding downward displacement of fork 80 and rod 44. A return spring 84 is connected between the rod 44 and the cartridge 32 and normally biases the rod upwardly toward a locking position the bolt 42 and latch 58. When the handle 38 is depressed, rod 44 moves downwardly in opposition to the tension of spring 84 and when pressure on the handle 38 is released, the tension of spring 84 urges the rod 44, bolt 42 and latch 58 back to locking positions. Therefore, whenever the doors are in the closed position, the tension of spring 84 insures that the doors remain in the locked position.

When the door is open, however, it is imperative that the bolt 42 and latch 58 remain in the unlocked positions so that the door may be swung back to the closed position without damaging the bolt 42, latch 58, beam 22 or sill 24. For this reason, a catch 86 is incorporated at the upper end of operating rod 44 to hold rod 44 in its downward position whenever the door is opened. Collar 88 fixed to the rod 44 at its upper end is engaged by the catch 86 as shown in FIG. 3 when rod 44 is moved downwardly to open the door. The catch 86 is pivoted on pin 90 secured to a bolt guide 92, and is biased toward the rod 44 by means of a coil spring 94. The catch 86 is shown engaging collar 88 in FIG. 3, and disengaged from collar 88 in FIG. 6 where bolt 42 would be in its locking position in cup 48 of FIG. 7. To move the catch 86 from the engaged to the disengaged position, an L-shaped release pin 96 is connected to the one end of catch 86. The release pin 96 rotates the catch 86 out of engagement with boss 88 by making contact with a shoulder 98 formed on the crossbeam 22 (FIG. 1) against which the doors butt at their upper ends. When the door is opened by means of the operating handle 38, the catch 86 engages the collar 88 and prevents the bolt 42 and latch 58 from moving to the locking position. As the door is closed,

bolt 42 registers with cup 48, the latch 58 moves over lip 66 and release pin 96 butts against the shoulder 98 releasing the catch 86 thereby permitting the rod 44 to translate upwardly to lock the door in its closed position.

While an orderly description of the mechanism employed in the present invention has made it desirable to postpone a discussion of the laterally displaceable mating edge elements 100 and 102 until this point, it will be seen and understood that these edge elements are of critical importance to the invention. These mating edge elements result in the free edges of the doors 14 and 16 being clamped against one another when the doors are locked (or one door being clamped against a door frame if the doors are installed singly). For this purpose an edge element 100 shown in FIGS. 1-4 and 6 is mounted to channel member 32 at the free edge of door 14. The edge element 100 can be displaced laterally of the door when it has been moved to its closed position and provides not only a tighter seal at the free edge of the door, but also closes any gaps which might be exposed to allow a pry to be inserted and forcible entry to be had.

As seen in FIGS. 1 and 6, the door 16 mating with door 14 also includes an edge element 102 which is mounted to the free edge of door 16. The confronting surfaces of the elements 100 and 102 have mating tongue-and-groove profiles. When the doors are in the closed and locked position as seen in FIG. 6, the edge elements areengaged and locked with one another and the laterally overlapping surfaces of the tongue-andgroove obscure direct access through a crack between the doors by means of a wire or other device which may be surreptiously probed through the doors from outside the building to unlatch the doors. The prospects of unauthorized entry being gained by probing through the door is particularly threatening where the doors include a large transparent glass panel such as pane 36 which provides a view of the operating handle from outside of a building. It will be understood that the element 100 will be pressed against the element 102 as described in greater detail below and because of the load applied to the element 100 from the door, manipulation of prying tools between the doors will be forestalled.

It will also be understood that where the door 14 is installed singly, the mating element 102 as seen in FIG. 6 may be attached directly to the door frame rather than to the free edge of an adjacent door. The invention, therefore, encompasses both single or double door installations and the security provided by the novel edge mechanism is improved over the prior art devices in each installation.

In embodiments where the elements 100 and 102 are mounted on the free edges of double doors, it may be desirable to open either one of the doors independent of the other. In such case, both of the doors have edge elements which may be independently displaced laterally by means of the operating handles sufficiently to clear the mating element on the opposite door. In other embodiments, however, it may be sufficient to provide a stationary edge element on one of the doors and a laterally displaceable element on the mating door. The present invention will be described in the context where both elements 100 and 102 are displaceable, and no bolt 42 or latch 58 is installed on door 16.

As mentioned above, the operating handle 38 on door 14 when pressed downwardly translates operating rod 44 downwardly by means of the fork 80 in a conventional fashion. As seen in FIGS. 2-5, the operating rod 44 is connected to a plurality of three-bar linkages which are connected to and cause the edge element 100 to be displaced laterally with respect to the free end of the door or channel member 32. Since the three-bar linkages and the connections with member 32, rod 44 and element 100 are identical, the same reference numerals will be applied to the corresponding links and connections and appropriate letter subscripts will be appended to the numerals where necessary to distinguish the specific mechanisms.

The three-bar linkages have a first link 104, a second link 106 and a third link 108. The link 104 is connected to operating rod 44 at a collar 110 which is fixedly secured to the rod 44. The second link 106 is connected to the end of link 104 opposite collar 110 and is also connected to a guide pin 112 which is secured to the element 100 by means of screw 114. Guide pin 112 extends laterally through a bushing 116 in cartridge 33 and through an aperture in the end surface of channel member 32. A coil spring 118 is interposed between the cartridge 33 and the confronting surface of element 100. The spring 118 urges element 100 in a lateral direction away from the channel member 32 and aids in keeping the element 100 generally aligned with the end surface of channel member 32. As seen by a comparison of the element 100 and spring 118 in FIGS. 3 and 4, the spring 118 is compressed when rod 44 has been moved downwardly to the open position whereby element 100 has been withdrawn toward the end surface of channel member 32 as in FIG. 3; conversely, spring 118 is extended to displace element 100 away from the end surface as in FIG. 4 when rod 44 has moved upwardly.

The third link 108 of the three-bar linkage is mounted to the second link 106 at a point generally intermediate the ends of link 106 and is also connected to the cartridge 33 at a pivot block 120. It will be noted that pivot block 120 is located substantially directly opposite the guide pin 112 which is connected to the element 100. As a consequence, when the operating rod 44 is displaced upwardly to the locking position and element 100 is extended and engaged with the mating element on either an adjacent door or a door frame, the two-bar linkages formed by links 106 and 108 are moved substantially into a toggle position in which the pivot points of link 108 are almost aligned with the connection of link 106 and guide pin 112. As is well known in the art, as the links displace into the toggle position, an extremely high mechanical advantage is achieved. With the small force applied to the two-bar linkage 106, 108 through the first link 104, a very large force can be applied between element 100 and mating element 102. The large force between the elements 100 and 102 not only seals the gaps between the elements but also resists any further loads which might be applied between the elements by means of a pry. The three-bar linkage therefore not only actuates the element 100 into a locking and sealing position, but also resists forcible entry as a virtually rigid structure. Any loads which attempt to displace element 100 laterally toward the door to which the element is mounted are reacted by the links 106 and 108 in substantially pure compression. The links 106 and 108 are in an optimum position for resisting the prying loads.

The first link 104 of the three-bar linkage located near the doorsill serves the additional function of actuating the latch 58. An interconnecting link 122 transmits motions of operating rod 44 to the latch 58.

As mentioned above, the operating rod 44 also includes the .bolt 42 integrally formed on the upper end of the rod 44. Displacement of rod 44 to the locking position by means of the spring 84 actuates the bolt 42, the latch 58 also the three-bar linkages which displace element 100. Spring 84 is also assisted by coil springs 118 which urge element 100 laterally away from the door 14. The connections between the rod 44 and the locking components are adjusted to engage each of the components at the locking position of rod 44 and to disengage the components at the unlocked position of rod 44. Therefore, actuation of handle 38 simultaneously disengages all of components and permits the door to be opened. The catch 86 which holds the operating rod 44 in its unlocked position also holds the element 100 in its withdrawn position due to the common operation of the element 100, bolt 42 and latch 58 by means of the rod 44. The common operation of the bolt 42, latch 58 and element 100 is advantageous since the actuation of any one of the components in normal usage requires actuation of the other elements as well. If desired, however, no impediment exists to providing an operating mechanism for the element 100 which is separate from the mechanism operating bolt 42 and latch 58; and, of course, the bolt 42 and latch 58 are eliminated entirely from the opposite door 16 in the preferred embodiment of the invention.

While the novel door assembly is disclosed in several embodiments, it will be obvious to those skilled in the art that various modifications and substitutions in the particular components can be made without departing from the spirit or purpose of the invention. In the embodiment described herein, door 16 has been described as having a displaceable element 102 but no bolt 42 or latch 58. Thus, door 16 is free to open while door 14 remains locked or both doors open together when the operating handle on door 14 is actuated. Element 102 could be fixed, however, to door 16 and then door 16 could only be opened with door 14. Various combinations of the movable edge elements and latch and bolt may be provided on double doors according to the particular needs of any given installation. Also, a single door could be provided with a movable edge element which mates with a door jam and no bolt or latch would be necessary. Accordingly, it should be understood that the novel door assembly as disclosed herein is described by way of illustration and not limitation.

What is claimed is:

l. A door assembly comprising:

a door frame;

a door having two oppositely disposed lateral edges, one edge being hinged to said frame and the opposite edge being a free edge, said door being movable between an open position and a closed position;

a laterally displaceable edge element mounted at the free edge of the door, said edge element having a projecting tongue, both said edge element and said tongue extending substantially the entire length of the free edge;

a mating element in said frame for mating engagement with said edge element in the closed position of said door, said mating element having a groove for mating engagement with said tongue, said tongue and said groove mating in said closed position of said door;

an operating handle mounted to the door for opening the door;

operating means interconnecting the operating handle and the laterally displaceable edge element for displacing the element laterally toward the door to disengage said tongue from said groove with the opening of the door by the operating handle, said operating means including a rod extending adjacent said free edge of the door and being movable between a locked position and an unlocked position; and

' toggle linkage means interconnecting said rod and said edge element, said toggle linkage means having a toggle position corresponding to the locked position of said rod.

2. The door assembly of claim 1 wherein:

said toggle linkage means includes a two bar linkage connection with said rod, said two bar linkage having a first link connected with said edge element and a second link connected to the first link and to said door at a position laterally opposite the connection of the first link with the edge element, the locations of the connection of said first link with the edge element and said second link with said first link and said second link with said door forming essentially a straight line in said toggle position of said linkage.

3. The door assembly of claim 2 including:

a spring-loaded catch means for automatically securing the linkage and the edge element in the withdrawn position with the opening of the door by the handle.

4. The door assembly of claim 3 further including:

releasing means connected to the spring-loaded catch means and actuated upon movement of said door to said closed position for releasing the catch means thereby permitting the edge element to move from the withdrawn position to mating engagement with said mating element, said releasing means including means responsive to approach of said door to the enclosed position thereof to release said catch.

5. The door assembly of claim 4 wherein:

a movable locking bolt is mounted on the door and is movable between a locking position and an unlocked position; and

the mechanical linkage of the operating means is also connected to the bolt for moving the bolt to the unlocked position with the opening of the door by the operating handle.

6. A door assembly comprising:

a door frame including two oppositely disposed lateral hinge posts, a doorsill connecting the hinge posts together at one end of the frame and a crossbeam connecting the hinge posts together at the other end of the frame;

two doors hung respectively on the two hinge posts of the door frame, each hung door thereby having a hinged edge and a laterally opposite free edge, the two doors in the closed position substantially filling the door frame;

bolting means mounted to one of the doors for locking the door to the door frame;

an edge element mounted to and extending along the free edge of at least one of the doors and being laterally displaceable into engagement with the free edge of the other door at the closed position of the doors;

operating means for actuating the edge element into and out of engagement with the free edge of said other door, said operating means including an operating rod extending substantially parallel to the free edge of said one door and being displaceable between a locking position and an unlocking position; and

a two-bar linkage connected with the operating rod, said linkage having a first link connected with the edge element and a second link connected to the first link and to said one door at a position laterally opposite the connection of the first link with the edge element, the two-bar linkage having a toggle position corresponding substantially with the locking position of the operating rod.

7. The door assembly according to claim 6 wherein:

the confronting surfaces of the edge element on the one door and the free edge of the other door have mating portions engaging in laterally overlapping relationship.

8. The door assembly of claim 7 wherein:

the mating portions have tongue-and-groove profiles.

9. The door assembly of claim 6 wherein:

a laterally displaceable edge element is mounted to and extends along the free edge of each door, the elements having mated, confronting surfaces engaging in laterally overlapping relationship at the closed position of the doors; and

said operating means are supported by each door and are connected respectively to the edge elements mounted on the respective doors for actuating the elements independently out of engagement with the other door.

10. The door assembly of claim 9 wherein:

said operating means supported by the door bearing the bolting means is additionally connected to the bolting means for unlocking the bolting means from the door frame simultaneously with the disengagement of the associated edge element.

11. The door assembly of claim 10 wherein:

bolting means are mounted to each door and are connected respectively to the said operating means of the respective doors for locking and unlocking the doors individually.

12. The door assembly of claim 6 wherein:

the bolting means is mounted near the free edge of the one door and includes a bolt having a projecting end, the projecting end of the bolt being slidable parallel to the free edge of the door toward a locking position with the crossbeam of the door frame; and

a spring biased, self-centering, bolt receiving cup is mounted on the crossbeam of the frame at the locking position of the bolt with the crossbeam.

13. The door assembly of claim 6 wherein:

latching means is mounted near the free edge of the one door and includes a latch mounted adjacent the doorsill, the latch having a projecting tang rotatable from the door toward a locking position with the doorsill; and

a tang-engaging lip extends along the doorsill at the locking position to engage the tang with the doorsill.

14. The door assembly of claim 13 wherein:

the tang-engaging lip extends the entire length of the sill and has an inner side which contacts the tang at the locking position and an outer side opposite the inner side; and weather strips are mounted on the doors and extend between the hinge posts in contacting relationship with the outer side of the lip at the closed position of the doors. 15. The door assembly of claim 6 wherein:

a third link is connected between the first link of the twobar linkage and the operating rod to form a three-bar linkage; and

a plurality of the three-bar linkages are connected between the operating rod and the edge element at the free edge of the door.

16. The door assembly of claim 15 wherein:

the one of the doors bearing the edge element is comprised of a hollow channel member at the free edge of the door;

the edge element is slidably mounted on the hollow channel member; and

the operating rod and the plurality of three-bar linkages are mounted within the hollow channel member.

17. The door assembly of claim 6 wherein:

said operating rod is connected to said bolting means, said edge element being engaged and disengaged with the other door and the bolt being locked and unlocked with the frame at the locking and unlocking positions of the operating rod respectively.

18. The door assembly of claim 17 wherein:

catching means are connected to the one of the doors for holding the rod in the unlocked position.

19. The door assembly of claim 18 wherein:

the catching means includes a releasing means; and

resilient means are connected between the operating rod and the one of the doors for biasing the operating rod toward the locking position.

20. The door assembly of claim 19 wherein:

the releasing means includes an actuating pin carried by the catching means in the one of the doors and contacting the frame at the closed position of the one of the doors.

21. A door assembly comprising:

a door frame including two oppositely disposed lateral hinge posts, a doorsill connecting the hinge posts together at one end of the frame and a crossbeam connecting the hinge posts together at the other end of the frame;

two doors hung respectively on the two hinge posts of the door frame and movable between open and closed positions, each hung door having a hinged edge and a laterally opposite free edge, the two doors in the closed position substantially filling the door frame;

bolting means on at least one of the doors for locking the door to the door frame;

a first edge element mounted on the free edge of one of said doors, said edge element having a projecting tongue, both said edge element and said tongue extending along substantially the entire free edge of said one door, said edge element being laterally displaceable with respect to .said one door;

a mating element on the free edge of the other door for mating engagement with said first edge element in the closed position of said doors, said mating element having a groove for mating engagement with said tongue;

operating means supported by said one door and connected to said first edge element for actuating said first edge elernent laterally into and out of engagement with said mating element on said other door, said operating means including an operating rod extending adjacent said free edge of said one door and being movable between a locked position and an unlocked position; and

toggle linkage means interconnecting said rod and said edge element, said toggle linkage means having a toggle position corresponding to the locked position of said rod.

22. The door assembly according to claim 21 including:

latch means for latching said one door to said doorsill, said latch means including a projecting tang rotatable from said one door into locking engagement with said doorsill.

23 The door assembly of claim 22 wherein:

said operating means 15 connected to said bolting means and to said latch means.

24. The door assembly of claim 22 including:

a lip having first and second sides extending along said doorsill, said tang engaging one side of said lip in the closed position of said door; and

weather strip means mounted on said doors and in contacting relationship with the other edge of said lip in the closed position of said doors.

25. The door assembly of claim 21 wherein:

said mating element on the free edge of said other door is laterally displaceable with respect to said other door; and including operating means on said other door for actuating said mating element with respect to said other door.

26. The door assembly of claim 21 wherein:

said bolting means is movable beyond the edge of said crossbeam; and including a spring biased, self-centering bolt receiving cup in said crossbeam to receive said bolting means in the closed position of said one door.

27. The door assembly of claim 21 wherein:

said operating rod extends substantially parallel to the free edge of the door; and

said toggle linkage includes at least one twobar linkage connected to the operating rod, said two-bar linkage having a first link connected to the edge element and a second link connected to the first link and to the door at a position laterally opposite the connection of the first link with the edge element, said two-bar linkage having a toggle position corresponding substantially with the locked position of the operating rod.

28. The door assembly of claim 27 wherein:

a third link is connected between the first link of the twobar linkage and the operating rod to form a three-bar linkage; and

a plurality of the three-bar linkages are connected between the operating rod and the edge element at the free edge of the door.

29. The door assembly of claim 21 wherein:

said operating means includes an operating rod displaceable between a locking position and an unlocking position; and including means biasing said rod toward said locking position;

catch means mounted on said one door for holding said rod in the unlocked position; and

means responsive to the approach of said one door to the closed position thereof for releasing said catch means upon movement of said one door to said closed position. 

1. A door assembly comprising: a door frame; a door having two oppositely disposed lateral edges, one edge being hinged to said frame and the opposite edge being a free edge, said door being movable between an open position and a closed position; a laterally displaceable edge element mounted at the free edge of the door, said edge element having a projecting tongue, both said edge element and said tongue extending substantially the entire length of the free edge; a mating element in said frame for matinG engagement with said edge element in the closed position of said door, said mating element having a groove for mating engagement with said tongue, said tongue and said groove mating in said closed position of said door; an operating handle mounted to the door for opening the door; operating means interconnecting the operating handle and the laterally displaceable edge element for displacing the element laterally toward the door to disengage said tongue from said groove with the opening of the door by the operating handle, said operating means including a rod extending adjacent said free edge of the door and being movable between a locked position and an unlocked position; and toggle linkage means interconnecting said rod and said edge element, said toggle linkage means having a toggle position corresponding to the locked position of said rod.
 2. The door assembly of claim 1 wherein: said toggle linkage means includes a two bar linkage connection with said rod, said two bar linkage having a first link connected with said edge element and a second link connected to the first link and to said door at a position laterally opposite the connection of the first link with the edge element, the locations of the connection of said first link with the edge element and said second link with said first link and said second link with said door forming essentially a straight line in said toggle position of said linkage.
 3. The door assembly of claim 2 including: a spring-loaded catch means for automatically securing the linkage and the edge element in the withdrawn position with the opening of the door by the handle.
 4. The door assembly of claim 3 further including: releasing means connected to the spring-loaded catch means and actuated upon movement of said door to said closed position for releasing the catch means thereby permitting the edge element to move from the withdrawn position to mating engagement with said mating element, said releasing means including means responsive to approach of said door to the enclosed position thereof to release said catch.
 5. The door assembly of claim 4 wherein: a movable locking bolt is mounted on the door and is movable between a locking position and an unlocked position; and the mechanical linkage of the operating means is also connected to the bolt for moving the bolt to the unlocked position with the opening of the door by the operating handle.
 6. A door assembly comprising: a door frame including two oppositely disposed lateral hinge posts, a doorsill connecting the hinge posts together at one end of the frame and a crossbeam connecting the hinge posts together at the other end of the frame; two doors hung respectively on the two hinge posts of the door frame, each hung door thereby having a hinged edge and a laterally opposite free edge, the two doors in the closed position substantially filling the door frame; bolting means mounted to one of the doors for locking the door to the door frame; an edge element mounted to and extending along the free edge of at least one of the doors and being laterally displaceable into engagement with the free edge of the other door at the closed position of the doors; operating means for actuating the edge element into and out of engagement with the free edge of said other door, said operating means including an operating rod extending substantially parallel to the free edge of said one door and being displaceable between a locking position and an unlocking position; and a two-bar linkage connected with the operating rod, said linkage having a first link connected with the edge element and a second link connected to the first link and to said one door at a position laterally opposite the connection of the first link with the edge element, the two-bar linkage having a toggle position corresponding substantially with the locking position of the operating rod.
 7. The door assembly according to claim 6 wherein: the Confronting surfaces of the edge element on the one door and the free edge of the other door have mating portions engaging in laterally overlapping relationship.
 8. The door assembly of claim 7 wherein: the mating portions have tongue-and-groove profiles.
 9. The door assembly of claim 6 wherein: a laterally displaceable edge element is mounted to and extends along the free edge of each door, the elements having mated, confronting surfaces engaging in laterally overlapping relationship at the closed position of the doors; and said operating means are supported by each door and are connected respectively to the edge elements mounted on the respective doors for actuating the elements independently out of engagement with the other door.
 10. The door assembly of claim 9 wherein: said operating means supported by the door bearing the bolting means is additionally connected to the bolting means for unlocking the bolting means from the door frame simultaneously with the disengagement of the associated edge element.
 11. The door assembly of claim 10 wherein: bolting means are mounted to each door and are connected respectively to the said operating means of the respective doors for locking and unlocking the doors individually.
 12. The door assembly of claim 6 wherein: the bolting means is mounted near the free edge of the one door and includes a bolt having a projecting end, the projecting end of the bolt being slidable parallel to the free edge of the door toward a locking position with the crossbeam of the door frame; and a spring biased, self-centering, bolt receiving cup is mounted on the crossbeam of the frame at the locking position of the bolt with the crossbeam.
 13. The door assembly of claim 6 wherein: latching means is mounted near the free edge of the one door and includes a latch mounted adjacent the doorsill, the latch having a projecting tang rotatable from the door toward a locking position with the doorsill; and a tang-engaging lip extends along the doorsill at the locking position to engage the tang with the doorsill.
 14. The door assembly of claim 13 wherein: the tang-engaging lip extends the entire length of the sill and has an inner side which contacts the tang at the locking position and an outer side opposite the inner side; and weather strips are mounted on the doors and extend between the hinge posts in contacting relationship with the outer side of the lip at the closed position of the doors.
 15. The door assembly of claim 6 wherein: a third link is connected between the first link of the two-bar linkage and the operating rod to form a three-bar linkage; and a plurality of the three-bar linkages are connected between the operating rod and the edge element at the free edge of the door.
 16. The door assembly of claim 15 wherein: the one of the doors bearing the edge element is comprised of a hollow channel member at the free edge of the door; the edge element is slidably mounted on the hollow channel member; and the operating rod and the plurality of three-bar linkages are mounted within the hollow channel member.
 17. The door assembly of claim 6 wherein: said operating rod is connected to said bolting means, said edge element being engaged and disengaged with the other door and the bolt being locked and unlocked with the frame at the locking and unlocking positions of the operating rod respectively.
 18. The door assembly of claim 17 wherein: catching means are connected to the one of the doors for holding the rod in the unlocked position.
 19. The door assembly of claim 18 wherein: the catching means includes a releasing means; and resilient means are connected between the operating rod and the one of the doors for biasing the operating rod toward the locking position.
 20. The door assembly of claim 19 wherein: the releasing means includes an actuating pin carried by the catching means in the one of the doors and contacting the frame at the closed position of the one of the doors.
 21. A door assembly comprising: a door frame including two oppositely disposed lateral hinge posts, a doorsill connecting the hinge posts together at one end of the frame and a crossbeam connecting the hinge posts together at the other end of the frame; two doors hung respectively on the two hinge posts of the door frame and movable between open and closed positions, each hung door having a hinged edge and a laterally opposite free edge, the two doors in the closed position substantially filling the door frame; bolting means on at least one of the doors for locking the door to the door frame; a first edge element mounted on the free edge of one of said doors, said edge element having a projecting tongue, both said edge element and said tongue extending along substantially the entire free edge of said one door, said edge element being laterally displaceable with respect to said one door; a mating element on the free edge of the other door for mating engagement with said first edge element in the closed position of said doors, said mating element having a groove for mating engagement with said tongue; operating means supported by said one door and connected to said first edge element for actuating said first edge element laterally into and out of engagement with said mating element on said other door, said operating means including an operating rod extending adjacent said free edge of said one door and being movable between a locked position and an unlocked position; and toggle linkage means interconnecting said rod and said edge element, said toggle linkage means having a toggle position corresponding to the locked position of said rod.
 22. The door assembly according to claim 21 including: latch means for latching said one door to said doorsill, said latch means including a projecting tang rotatable from said one door into locking engagement with said doorsill.
 23. The door assembly of claim 22 wherein: said operating means is connected to said bolting means and to said latch means.
 24. The door assembly of claim 22 including: a lip having first and second sides extending along said doorsill, said tang engaging one side of said lip in the closed position of said door; and weather strip means mounted on said doors and in contacting relationship with the other edge of said lip in the closed position of said doors.
 25. The door assembly of claim 21 wherein: said mating element on the free edge of said other door is laterally displaceable with respect to said other door; and including operating means on said other door for actuating said mating element with respect to said other door.
 26. The door assembly of claim 21 wherein: said bolting means is movable beyond the edge of said crossbeam; and including a spring biased, self-centering bolt receiving cup in said crossbeam to receive said bolting means in the closed position of said one door.
 27. The door assembly of claim 21 wherein: said operating rod extends substantially parallel to the free edge of the door; and said toggle linkage includes at least one two-bar linkage connected to the operating rod, said two-bar linkage having a first link connected to the edge element and a second link connected to the first link and to the door at a position laterally opposite the connection of the first link with the edge element, said two-bar linkage having a toggle position corresponding substantially with the locked position of the operating rod.
 28. The door assembly of claim 27 wherein: a third link is connected between the first link of the two-bar linkage and the operating rod to form a three-bar linkage; and a plurality of the three-bar linkages are connected between the operating rod and the edge element at the free edge of the door.
 29. The door assembly of claim 21 wherein: said operating means includes an operating rod displaceable Between a locking position and an unlocking position; and including means biasing said rod toward said locking position; catch means mounted on said one door for holding said rod in the unlocked position; and means responsive to the approach of said one door to the closed position thereof for releasing said catch means upon movement of said one door to said closed position. 